Conventional heat treatment processes, such as a batch oven heat treatment process and other heat treatment process techniques, involve prior art ovens that have been constructed from custom designs. These custom designs often involve custom components such as odd sized insulated panels of a standard tongue and groove construction with raw metal edges. Ductwork, for hot air distribution in these prior art ovens, is usually custom fitted into the oven structure so as to allow for even distribution of hot air for the designed application. Walls are then trimmed internally and externally using rows of fasteners through cosmetic as well as structural angular trim pieces, giving the structure permanency. The permanent structure is then supported using structural steel such as “T” beam, “C” channel, and tie angle to provide a skeletal framework for the shell to rest on or against. U.S. Pat. Nos. 3,977,824; 4,246,852; 4,249,888; 4,311,460; 4,764,108 and 5,475,958 are representative of prior art oven or furnace structures relying on additional frame structures to support their panels or walls.
The degree of custom construction associated with conventional heat treatment ovens and the like lends itself to limitations as to future adaptability of components when attempting to alter the structure to accommodate changes in the end user's needs as each different structure commonly requires further customization of fabricated framework, ductwork, and shell to achieve the new size and/or functionality requirements.
An example of such limitations can be seen in the requirements involved following investment in a batch process oven during a business' early years, when production quantities are relatively small. With increased production needs, the process of heat treating (baking, drying, etc.) usually graduates from small batch runs to some form of automated conveyance of a product. The customized structural components cannot effectively be recouped or reapplied to future oven structures because the cost to change or modify the structure becomes prohibitive.
U.S. Pat. No. 4,198,951 describes forming an oven roof or wall from modular panels, each of which comprises an inner fabric and an outer fabric, with each fabric formed with an angle iron framework and somewhat resilient tie bars welded at their ends to the angle iron framework. The skins are formed so as to have one skin project laterally over an adjacent skin so as to slidingly overlie therewith to accommodate expansion contracture. These modular panels of U.S. '951 are highly labor intensive in their manufacture and provide a panel not easily erected, particularly in the roof panel/slide panel interface or at sidewall corners.
U.S. Design Pat. No. D360,423 to the assignee of the present application, RAYPAUL Industries, is directed at a design for a screen print curing oven. The illustrated curing oven features latched curing oven panels which latches provides for rapid assembly and disassembly, but like the prior art, is at least partially supported by a (conveyor) frame structure and does not feature a stand alone modular panel. Accordingly, the oven in design D360,423 lacks the flexibility of the present invention.
U.S. Pat. No. 4,336,443 is directed at a modular bake oven for drying varnished electrical components, which includes a front oven section forming one-half of the top and side walls of the assembled oven and a rear oven section forming the other half. While providing an oven that can be readily assembled and disassembled, the components of the oven fail to provide a high degree of freedom in accommodating variations in usage requirements.